Magneto-transport measurements of CaSb\(_2\)  clarified a resistivity plateau under a weak magnetic field at 10 K and nonsaturating giant magnetoresistance, consistent with the existence of line nodes [1]}. Electrical resistivity measurements under pressure revealed the dome-shaped \(T_{\rm {c}}\)  variation without Lifshitz transition in the normal state [2]} and specific heat measurements signified the deviation from the BCS behavior [3]}, suggestive of the unconventional nature of superconductivity. On the other hand, \(^{121/123}\) Sb nuclear quadrupole resonance (NQR) measurements suggested an exponential decrease in the inverse relaxation rate 1/\(T_1\)  at low temperature, supportive of the conventional \(s\) -wave superconductivity with a full gap [4]}. The presence of cylindrical electron pockets with line nodes has been discussed in favor of topological superconductivity [5]} associated with the dominant interorbital pairing interaction with odd-parity pairing within the cylindrical FSs, similarly to the case of doped TIs [6]} and doped Dirac semimetals [7]}, [8]}. Topological superconductivity was also predicted based on the full computation of the \(Z_2\) -enriched symmetry indicators [9]}. Despite such intensive experimental and theoretical studies, there are no experimental reports on the band structure of CaSb\(_2\) . It is thus of great importance to experimentally clarify the electronic states of CaSb\(_2\)  to establish the interplay among nodal electrons, superconductivity, and topology.
